The present invention relates to a video switching device and particularly relates to a multiple input, multiple output video switching system for inserting commercial advertisements or inserts into a plurality of preprogrammed video (television) channel signals.
Typically, a cable company receives television or video composite signals, those signals being a composite of video or visual signals and the audio signals, via a satellite dish or other telecommunications network. In a large number of cases, the video composite signals for one or more television channels originate at a remote location distant from the cable television station. The programmed channel video signal is "beamed up" to a satellite and the satellite beams down the programmed channel signal to regional sections in the U.S. where the cable system is located. This telecommunications network is called the satellite up link for the cable system.
In a number of cable channels such as MTV, NICK, VH1, DISC, LIFE, A&E, T&N, ESPN, USA, FNN and CBN, some time is set aside during the hourly run of the programmed show or segment for local cable systems to pre-empt the advertisement spots on the channel in favor of local commercial inserts. These available time slots are called in the industry local avails. Typically, the local avails are one or two minute time periods and are found in the time block extending from 20 minutes until 36 minutes past the hour and in the time block from 50 past the hour until 6 minutes past the succeeding hour.
In order to signal cable systems that a local avail time block on a particular channel is coming up, each of the aforementioned channels include in the audio section of the video composite signal a DTMF (dual tone multi-frequency) signal both shortly before the local avail time segment and immediately at the leading time edge of the local avail. A further convention adopted by these channels is to issue DTMF signals to signal the lagging time edge of the local avail.
There is a known prior art device that monitors the incoming programmed channel video signal in order to detect the DTMF signals signifying the local avail time slot. After sensing the DTMF local avail signal, this device inserts a local commercial generally by operating a video switch that selects a locally generated commercial insert video signal from one input of the video switch as opposed to selecting the programmed channel video at the other input. However, this prior art device is only capable of inserting one commercial insert in a single channel. However, many of the local avail time slots from the various channels mentioned above overlap since the local avail slots generally fall within 10 minutes before and six minutes after the top of the hour and the half hour. Since the cable systems are not well equipped to utilize these prior art devices on a per channel basis and particularly in view of the fact that the video machines generating the commercial insert video signals must be independently operated per channel, most cable systems do not effectively use these local available time slots on the designated LA (local available) channels described above. Therefore, the cable system is losing revenue because of its inability to exploit these local avail time slots on all of the LA channels.
The present invention overcomes this disadvantage by utilizing a multiple input, multiple output video switch system, that has a video switch for each channel, and that is controlled by a remote control center sending command signals and commercial insert video signals to the switch over a telecommunications network that is generally independent of the programmed LA channels. It should be noted that "programmed channel" does not indicate whether the show or video segment played on that channel has been programmed sometime in the past or is currently a live presentation, but simply designates the general type of video signal that cable systems receive from various origination points. In any event, "programmed channel video signal" refers to the signal obtained via a satellite up link from a program origination center and received by a cable system other than the center transmitting the commercial inserts and commands in accordance with the present invention.